Saccharides with identical functional groups but with different spatial configurations have different chemical and biological properties. Stereochemisty is the study of the arrangement of atoms in three-dimensional space. Stereoisomers are compounds in which the atoms are linked in the same order but differ in their spatial arrangement. Compounds that are mirror images of each other but are not identical, comparable to left and right shoes, are called enantiomers. The following structures illustrate the difference between β-D-Glucose and β-L-Glucose. Identical molecules can be made to correspond to each other by flipping and rotating. However, enantiomers cannot be made to correspond to their mirror images by flipping and rotating. Glucose is sometimes illustrated as a “chair form” because it is a more accurate representation of the bond angles of the molecule. The “boat” form of glucose is unstable.